What happens when a perfectly elastic ball collides with a completely inelastic ball? It is shown that the outcome depends on the stiffness of each ball. A standard textbook problem in mechanics is to calculate the outcome of a head-on collision between two balls using conservation of momentum and kinetic energy. It is easily shown that the…

A loop-the-loop experiment usually involves a ball rolling around a vertical loop. A different version of the experiment is described where a nut was allowed to slide around a vertical loop. In both experiments there is a large decrease in kinetic energy when the ball or the nut first enters the loop.

Two balls on an incline can remain at rest if friction between the balls prevents them rolling down the incline. Results with various balls are presented to show how ball mass, diameter and friction affects the outcome. A stack of four identical balls is also examined.

In a traditional teaching approach, a physics course begins with mechanics, and generally the braking effect due to magnetic interactions is not mentioned among the various types of friction presented (static, sliding, rolling) because students will discover magnetism only in later chapters. In our didactic experience this traditional choice is…

Smartphones and their internal sensors offer new options for an experimental access to teach physics at secondary schools and universities. Especially in the field of mechanics, a number of smartphone-based experiments are known illustrating, e.g., linear and pendulum motions as well as rotational motions using the internal MEMS accelerometer and…

In this paper, we propose a simple yet generic and versatile method to measure the position of a moving body as a function of time. Apart from very basic equipment such as carts and wheels, only a laser pointer or a similar device and a smartphone are necessary. By attaching a source of light to a cart and video filming its movement on a…

We consider the operation of the hypothetical mechanical vehicle driven by an engine powered by small rockets introduced by P D Hanstead in the inaugural volume of this journal. Hanstead arrived at three contradictory conclusions regarding the change in velocity should some of the rockets malfunction at a particular time. This thought experiment…

Using Tracker, a popular video-based physics modeling tool, the position-time data of magnetically damped oscillations of a simple pendulum are acquired. Eddy currents are generated on an aluminum sheet as the magnetic pendulum bob passes over it and the induced magnetic field opposes that of the magnetic bob. This causes the damping. A…

Experimental results are presented on the collision of a superball with two different wood blocks. The results are in reasonable agreement with a simple collision model where kinetic energy is conserved, but better agreement is obtained if a small loss of kinetic energy is assumed, as observed. The physics is slightly more complicated than the…

So many fundamental physics problems involve rigid body rotation that mastery of the subject is essential to many science and engineering undergraduate degrees. Rigid body rotation is typically taught in introductory mechanics courses and while students are generally comfortable with the corresponding kinematic equations, torques and moments of…

A simple experiment for students is to measure the coefficient of restitution (COR) for a vertical bounce on a horizontal surface. In this paper, measurements are presented of the COR for a tennis ball bouncing at an oblique angle on a horizontal surface. Changes in the horizontal and rotation speeds were also measured, by filming the bounce with…

In recent years, with the more powerful functions of smartphones, the use of sensors integrated by mobile phones as an auxiliary tool for physical experiment teaching has become more popular. Combined with the related mobile phone apps, people easily can develop and expand the physical experiment contents of mechanics, optics, acoustic phenomena,…

The fact that a bungee jumper can reach an acceleration greater than the acceleration of gravity is, also from a physics point of view, intriguing. Taking only gravity into account, it can be explained by applying conservation of energy or by deriving carefully the equation of motion in a Newtonian approach. In this article we show how it can be…

Learning introductory quantum physics is challenging, in part due to the different paradigms in classical mechanics and quantum physics. Classical mechanics is deterministic in that the equations of motion and the initial conditions fully determine a particle's trajectory. Quantum physics is an inherently probabilistic theory in that only…

A series of demonstration experiments devoted to the relativity of translational motion in inertial and non-inertial reference frames is proposed. We recommend a simple algorithm for the formation of the ability to transform coordinates, speeds and accelerations during the transition from one reference system to another system moving…